The present invention relates to systems for measuring total and static pressure in a gas flowing through an enclosed duct and to a uniquely configured, unitary element useful in making such measurements.
Systems which regulate the flow of air through closed duct or conduits, as in central heating, ventilating and air conditioning systems, are commonly controlled in response to the velocity of flow as indicated by total and static pressure measurements taken at various stations throughout the ductwork. That is, since velocity of air flow is a function of the velocity pressure, which is equal to total pressure minus static pressure, the velocity may be determined and thus controlled in accordance with readings of total and static pressure. In the most common systems, both total pressure and static pressure are sensed at a plurality of points throughout the cross section of the duct at each measuring station. In order to provide acceptable levels of accuracy, some systems provide flow straightening means to reduce turbulence of the air stream in advance, i.e., on the upstream side of the pressure sensors. The total and static pressures sensed at the individual points are separately averaged in respective, common manifolds.
It is a principal object of the present invention to provide a novel and improved system for measuring total and static pressure of air flowing through an enclosed duct.
Another object is to provide an element of unique design for use in measuring total and static pressure of air flowing within a duct to achieve significant advantages over prior art elements of this type.
A further object is to provide a system for measuring total and static pressure of an air stream flowing through an enclosed duct wherein the static pressure readings are proportionately lower than the actual static pressure in the duct, thereby providing velocity pressure signals which are amplified with respect to actual velocity pressure of the air stream, but remain linearly related thereto.
Additional objects are to provide an air flow measuring element, and system incorporating such elements, for positioning in ductwork and having a tolerance of turbulent air flow, and a configuration providing both economy of fabrication and adaptability to use in a variety of applications.
Other objects will in part be obvious and will in part appear hereinafter.